WO2003091806A1

WO2003091806A1 - Method for removing photoresist

Info

Publication number: WO2003091806A1
Application number: PCT/JP2003/005336
Authority: WO
Inventors: Shigeru Yokoi; Kazumasa Wakiya; Takayuki Haraguchi
Original assignee: Tokyo Ohka Kogyo Co., Ltd.
Priority date: 2002-04-26
Filing date: 2003-04-25
Publication date: 2003-11-06
Also published as: AU2003235130A1; US8354215B2; CN1650235A; KR100781925B1; EP1550912A1; US20070298619A1; JP3516446B2; EP1550912A4; US20050176259A1; TWI304525B; KR20050006191A; JP2004029696A; TW200307186A; US20080280452A1; US20110000874A1; US20090291565A1

Abstract

A method for removing a photoresist, which comprises (I) a step of providing a photoresist pattern on a substrate having at least a copper (Cu) wiring and a dielectric layer and etching the dielectric layer selectively using the photoresist pattern as a mask, (II) a step of contacting the substrate after the step (I) with an ozone water and/or an aqueous hydrogen peroxide solution, and (III) a step of contacting the substrate after the step (II) with a photoresist removing solution comprising a quaternary ammonium hydroxide. The method allows, in the formation of a fine pattern on a substrate having at least a copper (Cu) wiring and a dielectric layer such as that using the dual damascene method, even in a process not comprising O2 plasma ashing treatment, the effective removal of a photoresist film and etching residues, without adverse effect on the permittivity of the dielectric layer and with the excellent corrosion resistance of a product.

Description

Description Photoresist stripping method Technical field

The present invention relates to a method for removing a photoresist provided on a substrate having at least copper (CU) wiring and a low dielectric layer. The present invention is particularly in the manufacture of semiconductor devices such as IC and LSI, it is suitably applied to a method of removing photoresist in a process not including 0 ₂ plasma mediation single step which is commonly conventionally. Background art

For semiconductor devices such as ICs and LSIs, a photoresist is applied uniformly on a conductive metal layer, insulating layer, or low dielectric layer formed by CVD deposition on a substrate such as silicon wafer, and this is selectively applied. After exposing and developing a photoresist pattern to form a photoresist pattern, and using this pattern as a mask to selectively etch the conductive metal layer, insulating layer and low dielectric layer deposited by CVD, and forming a fine circuit, It is manufactured by removing an unnecessary photoresist layer with a stripping solution.

In recent years, as semiconductor devices have become more highly integrated and chip sizes have shrunk, wiring circuits have become finer and more multilayered. In semiconductor devices, wiring delays due to the resistance (wiring resistance) of metal layers used and wiring capacitance have been increasing. And so on have come to be regarded as problems. For this reason, it has been proposed to use a metal having a lower resistance than aluminum (A 1), which has conventionally been mainly used as a wiring material, for example, copper (Cu). Recently, A 1 wiring (A 1, A 1 Two types of devices are used, one using metal wiring mainly composed of A1 such as 1 alloy, and the other using copper wiring (metal wiring mainly composed of Cu, such as Cu and Cu alloy). It has come to be.

In the formation of Cu metal wiring, the etching resistance of Cu is low, and a method of forming a Cu multilayer wiring without etching Cu using a dual damascene method is used. Various methods have been proposed for the dual damascene method. As an example, after stacking multiple layers of Cu layers and low dielectric layers (such as Si〇C layers) on a substrate, a photoresist layer is provided on the top layer, and then the photoresist layer is selected. Exposure and development to form a photoresist pattern (first photoresist pattern). After this first Etsu quenching the low dielectric layer Hotorejisutopa evening Ichin as a mask, 0 by ₂ plasma mediation single treatment such as stripping the first photoresist pattern, forming a via hole which communicates with the C u layer on the substrate I do. Next, a photoresist pattern (second photoresist pattern) is newly formed on the uppermost layer of the remaining multilayer stack, and the remaining low dielectric layer is partially etched using the photoresist pattern as a mask to form a wiring communicating with the via hole. A trench for forming a hole. Then after peeling the second Hotorejisutopa evening Ichin by 〇 ₂ bra Zumaatsushingu treatment or the like via holes Lumpur, by filling the C u by electrolytic plated or the like in the trench, the multilayer C u wiring is formed .

In some cases, a substrate provided with a barrier layer (such as a SiN layer or a SiC layer) serving as an etching stopper layer between the Cu layer and the low dielectric layer may be used. In such a case, after forming (etching) via holes and trenches, a photoresist stripping process is performed with the barrier layer exposed on the substrate remaining or after the barrier layer is removed, and then the via holes and trenches are formed. Fill the trench with Cu.

In such a dual damascene method, the Si-based residue (Si deposition) derived from the low dielectric layer is easily generated by the etching process for forming the via hole and the trench, the plasma assing process, and the like. Residue may be formed as Si deposition on the outer periphery of the opening. Residues derived from photoresist are also likely to be generated. Therefore, if these residues are not completely removed, problems such as a decrease in the yield of semiconductor production occur.

Thus conventionally, a metal wiring pattern formation employed a 0 ₂ plasma mediation single treatment for removing the photoresist pattern and etch ing after residue. However, as patterns become ultra-miniaturized, low-dielectric layers used in Cu wiring boards are made of materials with lower dielectric constants. Is in the process of being developed. Such low dielectric constant material (1 ow-k material) Is Atsushingu resistance is weak, or even is said that there is no Atsushingu resistance, when using a l ow _ k material, after etching, it is necessary to employ a process that does not perform 〇 ₂ plasma Atsu single step.

Therefore miniaturization in photolithography one of semiconductor device fabrication that multilayer is progressed, even in 0 ₂ plasma mediation single treatment is not performed processes which are conventionally conventionally same and processes employing the o ₂ plasma mediation single step There is an urgent need to develop a photoresist stripping method that is more or less excellent in photoresist stripping properties and that excels in removing post-etch residue.

In a dual damascene method using Cu wiring, when a substrate having a barrier layer (etching stopper layer) is used and the barrier layer is left on the Cu layer, the residue is removed after photoresist etching. Can perform the stripping treatment without directly contacting the Cu layer with the photoresist stripping solution, and accordingly, it is desirable to perform these stripping processes more efficiently.

Note that, in Japanese Patent Application Laid-Open No. H11-74180 (Patent Document 1), a semiconductor substrate using metal wiring such as A1 contains an oxidizing agent (hydrogen peroxide) before the photoresist is stripped. There is disclosed a technique in which a photoresist is stripped using a stripping solution after being washed with a cleaning solution having the same. As the above-mentioned stripping solution, Japanese Patent Application Laid-Open No. 63-147716 (Japanese Patent Application Laid-Open Publication No. 63-147716) discloses, in [001] of Document 1, together with a stripping solution containing alkanolamine as a main component and a fluorine-based stripping solution. One line is described (exemplary list) as using a tetramethylhydroxyl-ammonium (TMAH) -based stripping solution as described in reference 2). However, the stripping solution whose effect is actually confirmed in Patent Document 1 is a monoethanolamine-based stripper, and both Patent Documents 1 and 2 disclose a dual damascene method as contemplated by the present invention. There is no mention or suggestion of a suitable photoresist stripping method.

Japanese Patent Application Laid-Open No. 11-233405 (Patent Document 3) discloses that a photoresist pattern is made of an oxidizing agent and an organic acid after dry etching of a semiconductor substrate using metal wiring such as A1. A method of manufacturing a semiconductor device in which the semiconductor element is cleaned with a cleaning liquid and then removed with a resist stripping liquid is described, but the publication also confirms the effect. The stripping solution is of a monoethanolamine type, and there is no description or suggestion about a photoresist stripping method suitable for the dual damascene method as contemplated by the present invention.

Patent Document 1 Japanese Patent Application Laid-Open No. H11-1-7480

Patent Document 2 JP-A-63-147 7 16 8

Patent Document 3 Japanese Patent Application Laid-Open No. H11-123333 Disclosure of Invention

The present invention has been made in view of the above circumstances, the fine patterning of a substrate having at least copper (C u) wiring and Tei誘conductive layer, even in a process that does not perform 〇 ₂ plasma Atsu single treatment, after etching It is an object of the present invention to provide a photoresist stripping method which can effectively strip off the photoresist film and the etching residue, does not adversely affect the dielectric constant of the low dielectric layer, and has excellent anticorrosion properties. I do. To solve the above problems, the present invention provides:

(I) a step of selectively etching the low dielectric layer using a photoresist pattern provided on a substrate having at least copper (Cu) wiring and a low dielectric layer as a mask;

(I I) a step of contacting the substrate after the step (I) with ozone water and / or hydrogen peroxide water, and

(I I I) a step of contacting the substrate after the step (I I) with a photoresist stripper containing at least a quaternary ammonium hydroxide

And a method for removing a photoresist. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

(I) Process:

A known photolithography technique can be applied. For example, a copper (Cu) wiring is formed on a substrate such as a silicon wafer, and a low dielectric layer is formed thereon. Optionally, a barrier layer (etching stopper layer) on the Cu wiring as an intermediate layer Alternatively, an insulating layer or the like may be provided, and a plurality of layers may be stacked.

In the present invention, the copper (Cu) wiring includes both wiring made of pure copper and wiring made of a copper alloy containing copper as a main component (for example, A1-Si_Cu, A1-Cu, etc.). In the present invention, metal wiring other than Cu wiring, such as A1-based wiring, may be formed as the metal wiring. The formation of the metal layer is performed by CVD deposition, electrolytic plating, or the like, but is not particularly limited.

Examples of the barrier layer (etching stopper layer) include a SiN layer, a SiC layer, a Ta layer, and a TaN layer, but are not limited to these examples.

In the present invention, a material having a dielectric constant of 3 or less is particularly preferably used as the low dielectric layer. The dielectric constant is a proportional constant (ε) expressed by the relationship D = £ E, where D is the electric flux density and E is the electric field strength.

Examples of the low dielectric layer include black diamond (Applied Materials Co., Ltd.), Coral (Novelus Systems Co., Ltd.), Aurora (Japan ASM Co., Ltd.) (S i〇C) -based materials: “〇CD T-7”, “〇CD T-1 9”, “〇CD T-11”, “OCD T—31”, “OCD T—39” (all MSQ (methylsilsesquioxane) based materials such as Tokyo Ohka Kogyo Co., Ltd .; HSQ (hydroxysilsesquioxane) such as "OCD T_12" and "@CD T_32" (both from Tokyo Ohka Kogyo) Although a low dielectric constant material (low-k material) such as a system material is mentioned as a preferable one, it is not limited to these examples. The low-dielectric layer is formed by applying the low-k material (low-k material) exemplified above and baking it at a high temperature of usually 350 ° C. or more for crystallization.

Next, a photoresist composition is applied onto the low dielectric layer and dried, and then a photoresist pattern is formed by a known photolithography technique by exposure, development, and the like. The photoresist composition, Kr F, Ar F, F 2 excimer laser of all, there had the photoresist composition which are customary is preferably used for the electron beam, not limited in particular.

Exposure and development conditions can be appropriately selected depending on the photoresist used depending on the purpose. For the exposure, for example, active light such as ultraviolet light, far ultraviolet light, excimer laser, X-ray, electron beam, etc. The photoresist layer is exposed through a desired mask pattern by a light source emitting light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, or the like, or drawn on the photoresist layer while manipulating the electron beam. Thereafter, post-exposure baking (post-exposure baking) is performed as necessary.

The development method is not particularly limited.For example, a substrate coated with a photoresist is immersed in a developing solution for a certain period of time, then washed with water and dried, followed by immersion development, and the developing solution is dropped on the surface of the coated photoresist. Various developments can be performed according to the purpose, such as paddle development in which the sample is left for a certain period of time and then washing and drying, and spray development in which a developing solution is sprayed on the photoresist surface and then washed and dried.

Next, using the formed photoresist pattern as a mask, the low dielectric layer is selectively etched by dry etching or the like to form via holes or trenches (grooves for wiring). In the present invention, a dual damascene method or the like is suitably applied.

(I I) process:

The substrate after the etching step is brought into contact with ozone water and / or hydrogen peroxide water. The (II) step is intended to decompose the photoresist pattern, post-etch residue, etc., prior to the subsequent (III) step.

It is preferable to use ozone water in which ozone gas is dissolved in pure water by means such as publishing. The concentration of ozone is desirably 1 ppm or more to a saturation concentration. The aqueous solution of hydrogen peroxide is preferably an aqueous solution having a concentration of about 0.1 to 60% by mass, and particularly preferably an aqueous solution having a concentration of about 0.5 to 35% by mass.

Examples of the contacting method include an immersion method, a paddle method, and a shuffling method as described in the case of the developer treatment. Preferably, it is immersed in ozone water and Z or hydrogen peroxide water for about 5 to 60 minutes.

(I I I) Process:

The substrate after the step (II) is brought into contact with a photoresist stripper containing at least a quaternary ammonium hydroxide to remove a photoresist pattern and a residue after etching. The above quaternary ammonium hydroxide has the following general formula (I)

[Wherein, R 1, R ₂ , R ₃ , and R ₄ each independently represent an alkyl group having 1 to ₄ carbon atoms or a hydroxyalkyl group]

A quaternary ammonium hydroxide represented by the following formula is preferred. Specifically, tetramethylammonium hydroxide [= TMAH], tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, methyltripropylammonium hydroxide , Methyltriptylummonium hydroxide, trimethylethylammonium hydroxide, (2-hydroxyxetyl) trimethylammonium hydroxide [= choline], (2-hydroxixyl) triethylammonium Hydroxide, (2-hydroxyethyl) tripropylammonium hydroxide, (1-hydroxypropyl) trimethylammonium hydroxide and the like. Among them, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, methyltriptylammonium hydroxide, methyltrippyrmonammonium hydroxide, choline, etc. are Cu, Si-based residues. It is preferable from the viewpoint of the peelability of the object and the photoresist peelability. One or more quaternary ammonium hydroxides can be used.

The compounding amount of the quaternary ammonium hydroxide is preferably about 1 to 20% by mass, more preferably about 2 to 10% by mass in the photoresist stripping solution.

The photoresist stripping solution used in the present invention usually contains water and a water-soluble organic solvent in addition to the quaternary ammonium hydroxide. The mixing amount of water is preferably about 5 to 60% by mass, and particularly preferably 10 to 50% by mass. The balance is a water-soluble organic solvent. Examples of the water-soluble organic solvent include sulfoxides such as dimethyl sulfoxide; dimethyl sulfone, getyl sulfone, bis (2-hydroxyethyl) sulfone, and tetra. Sulfones such as ramethylene sulfone [nisulfolane]; amides such as N, N-dimethylformamide, N-methylformamide, N, N-dimethylacetamide, N-methylacetamide, N, N-getylacetamide Lactams such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-12-pyrrolidone, N-hydroxymethyl-12-pyrrolidone, N-hydroxyethyl-2-pyrrolidone; Imidazolidinones such as 3-dimethyl-2-imidazolidinone, 1,3-getyl 1-2-imidazolidinone, 1,3-diisopropyl-2-imidazolidinone; ethylene glycol, ethylene glycol monomethyl ether , Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol Monomethyl ether acetate, ethylene glycol-monoethyl ether acetate, diethylene glycol, diethylene glycol-monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol Examples include polyhydric alcohols such as monopropyl ether and propylene glycol monobutyl ether and derivatives thereof. Among them, dimethyl sulfoxide, dimethyl imidazolidinone, N-methyl-2-pyrrolidone, diethylene glycol monobutyl ether, sulfolane, N, N-dimethylacetamide, N, N-dimethylformamide and the like are preferably used. One or more water-soluble organic solvents can be used.

The photoresist stripping solution may further contain a water-soluble amine, if desired. Examples of the water-soluble amines include monoethanolamine, diethanolamine, triethanolamine, 2- (2-aminoethoxy) ethanol, N, N-dimethylethanolamine, N, N-getylethanolamine, N, N-dibutylamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-methylgenethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, etc. Lucanoamines: diethylenetriamine, triethylenetetramine, propylene Polyalkylenepolyamines such as rangeamine, N, N-getylethylenediamine, 1,4-butanediamine, N-ethyl-ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,6-hexanediamine 2-ethylethylhexylamine, dioctylamine, triptylamine, tripropylamine, triarylamine, heptylamine, aliphatic amines such as cyclohexylamine; aromatic amines such as benzylamine, diphenylamine, etc .; piperazine, N-methyl-piperazine And cyclic amines such as methyl-piperazine and hydroxyethylpiperazine. Above all, monoethanolamine, 2- (2-aminoethoxy) ethanol, N-methylethanolamine and the like are preferably used from the viewpoints of removal of photoresist jetting residue and corrosion resistance to metal wiring. When a water-soluble amine is blended, the blending amount is preferably about 10 to 50% by mass in the photoresist stripping solution.

In addition, from the viewpoint of removing the releasability, a carboxyl group-containing acidic compound, a salt of hydrofluoric acid with a base containing no metal ion, or the like may be further blended.

As the carboxyl group-containing acidic compound, acetic acid, propionic acid, glycolic acid and the like are preferred. When an acidic compound having a propyloxyl group is blended, the amount is preferably about 2 to 20% by mass in the photoresist stripping solution. Preferred examples of the salt of hydrofluoric acid and a base containing no metal ion include ammonium fluoride. When a salt of hydrofluoric acid and a salt group containing no metal ion is blended, the amount is preferably about 0.1 to 10% by mass in the photoresist stripping solution.

If necessary, the photoresist stripping solution may further include a barrier layer (an etching stopper layer) as an intermediate layer, or a barrier layer provided with a barrier layer. If the photoresist is removed after the layer is removed by etching, select from aromatic hydroxy compounds, benzotriazole-based compounds, and compounds containing a mercapto group as anticorrosives in view of the anticorrosion properties of CU wiring, etc. It is desirable to mix at least one of them. Specific examples of the aromatic hydroxy compound include phenol, cresol, Xylenol, pyrocatechol [= 1,2-dihydroxybenzene], tert-butylcatechol, resorcinol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, salicyl alcohol, p-hydroxybenzyl alcohol, o-hydroxybenzyl Alcohol, p-hydroxyphenethyl alcohol, p-aminophenol, m-aminophenol, diaminophenol, aminoresorcinol, p-hydroxybenzoic acid, 0-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid , 2,5-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, gallic acid and the like. Among them, pyrocatechol, pyrogallol, gallic acid and the like are preferably used. One or more aromatic hydroxy compounds can be used.

The benzotriazole-based compound is represented by the following general formula (II)

(In the formula, R ₅ and R ₆ each independently represent a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, a propyloxyl group, an amino group, a hydroxyl group, a cyano group, a formyl group, Represents a sulfonylalkyl group or a sulfo group; Q represents a hydrogen atom, a hydroxyl group, a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms (provided that the structure has an amide bond or an ester bond, May be used), aryl group, or the following formula

(III)

R ₇ — N, (III)

R ₉

(In the formula (III), R ₇ represents an alkyl group having 1 to 6 carbon atoms; R ₈ and R _{9 each} independently represent a hydrogen atom, a hydroxyl group, or a hydroxy group having 1 to 6 carbon atoms. Represents an alkyl group or an alkoxyalkyl group).

A benzotriazole-based compound represented by the formula:

In the present invention, in each definition of the above groups Q, R ₅ and R ₆ , the hydrocarbon group is preferably It may be either an aromatic hydrocarbon group or an aliphatic hydrocarbon group, may have a saturated or unsaturated bond, and may be a straight-chain or branched chain. Examples of the substituted hydrocarbon group include a hydroxyalkyl group and an alkoxyalkyl group. In the case of a substrate on which pure Cu wiring is formed, in the general formula (II), Q is particularly preferably a group represented by the above formula (III). Among them, in formula (III), it is preferable to independently select a hydroxyalkyl group or an alkoxyalkyl group having 1 to 6 carbon atoms as R ₈ and R ₉ .

In the general formula (II), those which represent a water-soluble group as Q are also preferably used. Specifically, a hydrogen atom, an alkyl group having 1 to 3 carbon atoms (that is, a methyl group, an ethyl group, a propyl group, or an isopropyl group), a hydroxyalkyl group having 1 to 3 carbon atoms, a hydroxyl group, or the like is an inorganic material. When a layer (for example, a polysilicon film, an amorphous silicon film, etc.) is provided on the substrate, it is preferable in terms of its corrosion resistance.

Specific examples of the benzotriazole-based compound include, for example, benzotriazole, 5,6-dimethylbenzotriazole, 1-hydroxybenzotriazole, 1-methylbenzotriazole, 1-aminobenzotriazole, 1-phenyl Benzotriazole, 1-hydroxymethylbenzotriazole, 1-methylbenzotriazolecarboxylate, 5-benzotriazolecarboxylic acid, 1-methoxybenzotriazole, 1_ (2,2-dihydroxy) Butyl) -benzotriazole, 1- (2,3-dihydroxypropyl) benzotriazole, or 2,2 '— ([[( 4-Methyl-1H-benzotriazole_1-yl) methyl] imino} bisethanol, 2, 2 '-{[( 5 _Methyl-1H-benzotriazole-1-yl) methyl] imino} bisethanol, 2, 2 '— {[(4-Methyl-1H-benzotriazo-1-ru-1methyl) imino} bisetane And 2,2 ′-{[(4-monomethyl_1H-benzotriazole_1-yl) methyl] imino} bispropane. Among them, 1- (2,3-dihydroxypropyl) -benzotriazol, 2, 2 '-{[(4-methyl-1H-benzotriazol-1-11) methyl] imino} bisethanol, 2, 2 '-{[(5-Methyl-1H-benzotriazoyl-11-yl) methyl] imino} bisphenol is preferably used. One or more benzotriazole compounds can be used.

As the above-mentioned mercapto group-containing compound, a compound having a structure having a hydroxyl group and a Z or hydroxyl group in at least one of the 3-position and the 3-position carbon atom bonded to the mercapto group is preferable. Specific examples of such compounds include 1-thioglycerol, 3- (2-aminophenylthio) -2-hydroxypropylmercaptan,

3- (2-Hydroxyethylthio) 1-2-hydroxypropylmercaptan, 2-mercaptopropionic acid, 3-mercaptopropionic acid and the like are preferred. Among them, 11-thioglycerol is particularly preferably used. One or more mercapto group-containing compounds can be used.

When an aromatic hydroxy compound, a benzotriazole-based compound, or a mercapto group-containing compound is compounded, the compounding amount varies depending on the photoresist stripping solution used. It is preferable to mix them by about 1 to 10% by mass, and it is particularly preferable to mix them by about 0.5 to 5% by mass. The upper limit of the total compounding amount is preferably about 15% by mass or less. The photoresist stripping solution used in the present invention may further contain an acetylene alcohol'alkylene oxide adduct obtained by adding an alkylene oxide to acetylene alcohol from the viewpoint of improving permeability.

As the acetylene alcohol, the following general formula (IV)

R11

R ₁₀ — C≡C— C— OH (IV)

R ₁₂

(However, R ,. is a hydrogen atom or the following formula (V)

13

― C— OH (V)

π14

Represents a group represented by; Ru, R ₁₂ , R ₁₃ , and R ₁₄ each independently represent a hydrogen atom, Represents an alkyl group with 1 to 6 elementary atoms)

The compound represented by is preferably used.

This acetylenic alcohol is commercially available as a series of, for example, “Surfinol” and “Olfine” (both are manufactured by Air Product and Chemicals Inc.), and is suitably used. Among them, “Surfinol 104”, “Surfinol 82” or a mixture thereof is most preferably used in view of its physical properties. In addition, “Olfin B”, “Olfin P”, “Olfin Y” and the like can be used.

As the alkylene oxide to be added to the acetylene alcohol, ethylene oxide, propylene oxide or a mixture thereof is preferably used. In the present invention, an acetylene alcohol · alkylene oxide adduct represented by the following general formula (VI) 16

R ₁₅ — C≡C— C— 0 ~ ("CH ₂ CH ₂ 0) ~ H (VI)

R17

(However, R ₁₅ is a hydrogen atom or the following formula (VII)

R ₁₆ , R ₁₇ , R ₁₈ , and R ₁₉ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)

The compound represented by is preferably used. Here, (n + m) represents an integer from 1 to 30, and the properties such as solubility in water and surface tension vary slightly depending on the number of added ethylene oxide.

Acetylene alcohol / alkylene oxide adduct is a substance known per se as a surfactant. These are commercially available as “Safinolol” (manufactured by Air Product and Chemicals Inc.) or “Acetyleneol” (manufactured by Kawaken Fine Chemicals Co., Ltd.) and are preferably used. Above all, consider changes in properties such as solubility in water and surface tension due to the number of ethylene oxide added. Considering this, “Safinolol 440” (n + m = 3.5), “Surfinol 465” (n + m = 10), “Sufinol 485” (n + m = 30), “Acetyleneol EL” (n + m m = 4), “acetylenol EH” (n + m = 10), or a mixture thereof is suitably used. Particularly, a mixture of “acetylenol EL” and “acetylenol EH” is preferably used. Among them, a mixture of “acetylenol EL” and “acetylenol EH” in a ratio of 2: 8 to 4: 6 (mass ratio) is particularly preferably used.

By blending this acetylene alcohol / alkylene oxide adduct, the permeability of the stripping solution itself can be improved, and the wettability can be improved.

When the acetylene alcohol / alkylene oxide adduct is compounded in the stripping solution of the present invention, the compounding amount is preferably about 0.05 to 5% by mass, and particularly preferably about 0.1 to 2% by mass.

The photoresist stripping solution used in the present invention can be advantageously used for photoresists that can be developed with aqueous solutions, including negative and positive photoresists. Such photoresists include (i) a positive photoresist containing a naphthoquinonediazide compound and a novolak resin; (ii) a compound that generates an acid upon exposure to light; (Iii) a compound that generates an acid upon exposure to light, a soluble resin having a group that is decomposed by an acid and increases the solubility in an aqueous solution of an aqueous solution And (iv) a compound capable of generating an acid by light, a negative photoresist containing a crosslinking agent and a soluble resin, and the like, but is not limited thereto.

In the step (III), the photoresist stripping solution is brought into contact with the substrate that has undergone the step (ii) to remove and remove the post-etching residue and the photoresist pattern. The contact method is not particularly limited, but is usually applied by an immersion method, a paddle method, or a spray method. The stripping time is not particularly limited as long as it is a time sufficient for stripping. In the present invention, prior to the removal step using a stripping solution, a decomposition treatment using ozone water and sulfuric acid or hydrogen peroxide water is performed. Without subjected to photoresist stripping solution at 0 ₂ plasma mediation single treatment because of the release treatment containing at least hydroxide, equivalent to that or more exfoliation effect post-etch residue, removing the photoresist pattern And the low dielectric layer has excellent corrosion protection. Therefore, even on a substrate on which a low dielectric layer (10W-k layer), which is said to have almost no ashing resistance, there is no adverse effect such as a change in the dielectric constant of the low dielectric layer, and there is no corrosion. Excellent photoresist stripping effect can be obtained.

After the above-mentioned stripping step, a rinsing process and a drying process using a conventionally-used organic solvent, water, or the like may be performed. As the organic solvent, a lower alcohol is preferable, and among them, isopropyl alcohol and the like are preferably used.

As the dual damascene method suitably applied to the present invention, a known method can be used. A “via first” method in which a via hole is formed first and then a trench is formed, and a via hole is formed after the trench is formed It may include, but is not limited to, any of the “trench first” methods.

In the “via first method”, the low dielectric layer is etched using the photoresist pattern (first photoresist pattern) as a mask to communicate with the metal layer on the substrate (when a substrate having a barrier layer is used). Is connected to the metal layer via a barrier layer) to form a via hole, and is then contacted with a photoresist stripping solution used in the present invention to strip the first photoresist pattern. Subsequently, a new photoresist pattern (second photoresist pattern) is formed on the remaining low dielectric layer, and the low dielectric layer is partially etched using this as a mask to form a trench communicating with the via hole. . Thereafter (when a substrate having a barrier layer is used, before etching or removing the barrier layer exposed on the substrate, or after removing the barrier layer), the substrate is brought into contact with the photoresist stripping solution used in the present invention, and Strip the second photoresist pattern.

On the other hand, in the “trench first” method, a low-dielectric layer is first etched to a predetermined thickness using a photoresist pattern (first photoresist pattern) as a mask to form a trench, and then the photoresist used in the present invention is used. Contact with stripper Then, the first photoresist pattern is peeled off. Subsequently, a new photoresist pattern (second photoresist pattern) is formed on the remaining low dielectric layer, and using this as a mask, the low dielectric layer is etched in communication with the trench, and the lower part is formed on the substrate. A via hole is formed that communicates with the Cu layer (if a substrate having a barrier layer is used, it communicates with the Cu layer on the substrate via the barrier layer). After this (when a substrate having a barrier layer is used, before the barrier layer exposed on the substrate is removed by etching or after the barrier layer is removed), the substrate is brought into contact with the photoresist stripping solution used in the present invention. To peel off the second photoresist pattern.

After any of the above steps, the via holes and trenches are filled with Cu by electrolytic plating or the like, thereby forming a multilayer Cu wiring. Example

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In addition, the compounding amount is shown by mass% unless otherwise specified.

Examples 1 to 6

TDUR-P722 (Tokyo Ohka Kogyo Co., Ltd.) is a positive photoresist on a substrate on which a Cu wiring is formed and an Si〇C layer (Carbon-butoxide layer; low-k layer) is laminated on top of it. Co., Ltd.) and heated at 140 ° C. for 90 seconds to form a photoresist layer. This was selectively exposed using S—203B (manufactured by Nikon Corporation), followed by post-exposure baking at 140 ° C. for 90 seconds, and 2.38% by mass A photoresist pattern was formed by developing with an aqueous solution of ammonium hydroxide (TMAH). The SiOC layer was then etched. The substrate after the above etching treatment is brought into contact with ozone water obtained by bubbling ozone gas with pure water for 15 minutes for 15 minutes. Subsequently, a photoresist stripper having a composition shown in Table 1 below (stripping) The solution was immersed (60 ° C, 30 minutes) in liquids A to F).

When the substrate surface at this time was observed by SEM (scanning electron microscope), The photoresist pattern and the etching residue were completely removed. No corrosion of the low dielectric layer was observed.

Example 7-: L 2

The substrate after the etching treatment obtained in the same manner as in Examples 1 to 6 above was brought into contact with a 30% by mass hydrogen peroxide solution heated to 60 for 30 minutes. Subsequently, a photoresist stripper having the composition shown in Table 1 below ( It was immersed (60 ° C, 30 minutes) in stripper A to F)

Observation of the substrate surface with a scanning electron microscope (SEM) revealed that the photoresist pattern and etching residues were completely removed. No corrosion of the low dielectric layer was observed.

Comparative Examples 1 to 6

The substrates after the etching treatment obtained in the same manner as in Examples 1 to 6 were treated in exactly the same manner as in Examples 1 to 6, except that the step of bringing into contact with ozone water was omitted.

Observation of the substrate surface at this time with a scanning electron microscope (SEM) revealed that the photoresist pattern and etching residue remained on the substrate surface without being completely removed.

table 1

Compound component (mass! 0

TPAH related water PGA DGA IR42 1-year-old stripper A

(5) (31) (40) (20) (2) -Le (2)

TBAH stake P water DGA IR42 1-year-old stripper B

(5) (30) (30) (32) (1) -le (2)

TPAH drawing P water DGA IR42 チ "!" Stripper C

(5) (22.5) (40) (30) (1) Rule (1.5)

TPAH NMP Water EA IR42 Stripper D

(5) (33) (40) (20) (2)

TPAH NMP Water DGA

(15) (17) (35) (30) -Le (3)

TPAH NMP Water DGA IR42 1-inch

(5) (32.5) (20) (40) (1) -le (1.5) The components shown in Table 1 are as follows.

TPAH: Tetrapropylammonium hydroxide

TBAH: Tetrabutylammonium hydroxide

NMP N-Methyl-1-pyrrolidone

DGA 2-(2-aminoethoxy) ethanol

MEA monoethanolamine

I R42: 2, 2 '_ {[(4-Methyl-1H-benzotriazoyl-1-yl) methyl] imino} bisethanol

Example 13-: 18

A positive type photoresist is formed on a substrate on which a Cu wiring is formed, and a SiN layer (barrier layer) and a Si〇C layer (carbon-doped oxide layer; low-k layer) are sequentially stacked on top of it. A certain TDUR-P722 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied and heated at 140 ° C. for 90 seconds to form a photoresist layer. This was selectively exposed using S-203B (manufactured by Nikon Corporation), followed by a post-exposure bake treatment at 140 ° C. for 90 seconds, and 2.38% by mass of tetraammonium hydroxide ( (TMAH) aqueous solution to form a photoresist pattern. Next, the S i OC layer was etched.

The substrate after the above etching treatment is brought into contact with ozone water obtained by bubbling ozone gas against pure water for 15 minutes for 15 minutes. Subsequently, a photoresist stripper having a composition shown in Table 2 below (stripping solution G ~ L) (60 ° C, 30 minutes).

When the substrate surface at this time was observed with a scanning electron microscope (SEM), the photoresist pattern and the etching residue were completely removed. No corrosion of the low dielectric layer was observed.

Examples 19 to 24

The substrate after the etching treatment obtained in the same manner as in Examples 13 to 18 above was brought into contact with a 30% by mass hydrogen peroxide solution heated to 60 ° C. for 30 minutes, followed by a photoresist composition having the composition shown in Table 2 below. Immerse in stripping solution (stripping solution G ~ L) (60t: for 30 minutes) Other than that, it processed similarly to Examples 13-18.

Observation of the substrate surface at this time with a scanning electron microscope (SEM) revealed that the photoresist pattern and etching residues were completely removed. No corrosion of the low dielectric layer was observed.

Comparative Example 7-: L 2

The photoresist stripping solution having the composition shown in Table 2 below without subjecting the substrate after the etching treatment obtained in the same manner as in Examples 13 to 18 to contact with ozone water and / or hydrogen peroxide solution. (Removal liquids G to L).

Table 2

The components shown in Table 2 are as follows.

T MAH: Tetramethylammonium hydroxide

Chol ine: (2-hydroxyethyl) trimethylammonium hydroxide (= Choline)

TP AH: Tetrapropylammonium hydroxide

TBAH: tetrabutylammonium hydroxide

MTPAH: Methyltripropylammonium hydroxide

MTBAH: Methyltributylammonium hydroxide

DMSO: dimethyl sulfoxide

NMP: N-methyl-2-pyrrolidone

S L F: Sulfolane

DGA: 2- (2-aminoethoxy) ethanol

According to the present invention as described in detail above, in forming a fine pattern of the substrate that have a at least Cu wiring low dielectric layers, even in the process is not performed 〇 ₂ plasma Atsu single treatment, the photoresist film after etching In addition, a photoresist stripping method capable of effectively stripping the etching residue, having no adverse effect on the dielectric constant of the low dielectric layer, and having excellent corrosion resistance of the low dielectric layer is provided. Industrial applicability

As described above, the photoresist stripping method of the present invention is applied to the formation of fine patterns using at least a substrate having Cu wiring and a low dielectric layer, such as a dual damascene method, and in particular, semiconductors such as ICs and LSIs. In the manufacture of devices and the like, the method is suitably applied to a photoresist stripping method in a process that does not include an O ₂ plasma ashes step, which has been conventionally used.

Claims

The scope of the claims

1. (I) a step of selectively etching the low dielectric layer using a photoresist pattern provided on a substrate having at least copper (Cu) wiring and a low dielectric layer as a mask,

(I I) a step of bringing the substrate after the step (I) into contact with ozone water and / or hydrogen peroxide water, and

A photoresist stripping method.

2. The method according to claim 1, wherein the low dielectric layer has a dielectric constant of 3 or less.

3. The quaternary ammonium hydroxide has the following general formula (I):

Rl

R ₂ — N— R4 OH "(R

R ₃

[Wherein, R 1, R ₂ , R ₃ , and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl group]

The method for detaching a photoresist according to claim 1, which is a quaternary ammonium hydroxide represented by the following formula:

4. The photoresist stripper according to claim 1, wherein the photoresist stripper contains 1 to 20% by mass of quaternary ammonium hydroxide, 5 to 60% by mass of water, and a water-soluble organic solvent. Method.

5. The water-soluble organic solvent is selected from dimethyl sulfoxide, dimethyl imidazolidinone, N-methyl-2-pyrrolidone, diethylene glycol monobutyl ether, sulfolane, N, N-dimethylacetamide, and N, N-dimethylformamide 5. The photoresist stripping method according to claim 4, wherein the method is at least one kind.

6. The photoresist stripping method according to claim 1, wherein the photoresist stripping solution further contains a water-soluble amine.

7. The photoresist stripping method according to claim 1, wherein the photoresist stripping solution further contains at least one selected from an aromatic hydroxy compound, a benzotriazole-based compound, and a mercapto group-containing compound.

8. The photoresist removing method according to claim 1, which is used in a dual damascene structure forming process.